<!DOCTYPE html>
<meta charset="utf-8">
<style>
body, html {
    margin: 0;
    font-size: 36px;
}
div {
    position: absolute;
}
#a {
    left: 0;
}
#b {
    right: 0;
}
</style>
<div id=a>A</div><div id=b>B</div>

